Some contacts not syncing from iPhone to iCloud

Approximately 30 contacts on my iPhone (out of ~1200) are not syncing to iCloud.

I've checked out this support article-

If your iCloud Contacts, Calendars, or Reminders won’t sync - Apple Support

I have tried each of these steps-

Restarted Contacts app

Refreshed Contacts

Check App Settings to make sure All iCloud is selected

Set iCloud Contacts as the default

>> Made sure the missing contacts are in the All iCloud group

Restarted the iPhone

And yet these contacts don't sync to iCloud or my Mac. If I add the contacts on my Mac, they will sync to the phone. The phone then tells me there is a duplicate contact, merges them, and then the newly created one is no longer on the Mac.

Any suggestions to fix?

Thanks!